The present invention relates to data storage devices. More specifically, the present invention relates to a method and apparatus for reading data from an optical card.
Efforts are continually being made to increase portability of notebook computers. Portability can be enhanced by reducing the size and weight of the notebook computer. Portability can also be enhanced by reducing power consumption. Lowering power consumption can increase battery life and extend the time that the notebook computer can be used without an ac adapter.
Most notebook computers include an internal CD-ROM drive. However, the CD-ROM drive tends to increase the size and weight of the notebook computer.
Additionally, the CD-ROM drive has a number of components. A typical CD-ROM drive includes optics for reading data from a CD-ROM disc, a retractable carrier for the CD-ROM disc, and motors for spinning a CD-ROM disc and retracting the carrier. Each component is subject to failure. Each component also adds to the cost of the CD-ROM drive.
The CD-ROM drive also consumes battery power. Operating the motors, especially the motor that spins the disc, drains the battery of the notebook computer.
Optical readers other than CD-ROM drives have been proposed. Among the proposed optical readers is an optical card reader. The optical card reader reads data stored on an optical card or OC-ROM, perhaps the size of a credit card, without any mechanical movement. To read data from the OC-ROM, the optical reader steers a beam of light across data patches on an upper surface of the OC-ROM. The data patches, and a lenslet array within the OC-ROM, cause bit images to be focused onto a detector array of the optical reader. The bit images are detected by the detector array and read out to electronics for further processing. Such an optical card reader allows large amounts of data to be stored on and read out from a single OC-ROM. Additionally, the OC-ROM is compact, low in cost, rugged, and factory-publishable. Reading the OC-ROM uses less power than reading a CD-ROM disc.
However, a steering lens and other optics (e.g., curved mirrors, beam splitters), which steer the beam across the OC-ROM, cause the optical reader to have a high profile, too high to be considered practical for use in a portable device such as a notebook computer. Moreover, the steering lens and the other optics add to the cost and weight of the optical card reader.
There is a need for a high capacity data storage device that has a lower profile and lighter weight than the CD-ROM drive and the optical card reader. There is also a need for a high capacity storage device that consumes less power and has a lower cost than the CD-ROM drive and the optical card readers.